This invention relates the packaging of bulk materials formed into a bale, pack or the like.
In particular, the present invention is concerned with but not restricted to the handling of baled material such as straw or silage or other material in like divided form for use as animal feedstock.
It has been proposed to wrap bales by means of a continuous strip of plastics material one of whose characteristics of use is that it has to be prestretched by an optimum amount in order that it will be effective as a bale wrapping material. The bale is wrapped in such manner that the baled material is effectively totally enclosed or shrouded in several layers of the plastics strip. To achieve the required wrapping it is necessary to wrap the bale in such manner that all air is excluded from the baled material and that respiration of the baled material is prevented.
In order to obtain and ensure the requisite air tightness the wrapping strip of plastics material, which is delivered to a wrapping position from a reel thereof, has to be maintained under a tension controlled within predefined limits. In addition, in order to achieve the total plastics enclosure it has been found necessary to be able to rotate the bale about two axes at right angles to each other. In the case of the so-called `big` bale which has a cylindrical shape it is necessary to rotate the bale about its longitudinal axis and also about a second axis transverse to the longitudinal axis and passing through the centre of the bale. In addition, the rotation of the bale in these two directions of rotations is such that the each part of the surface thereof is progressively moved into a setting in which it can be brought into the wrapping position. It is also to be noted that the preferred wrapping technique is in the end-to-end sense accompanied with rotation of the bale through a predetermined angle about its longitudinal axis at the finish of each end-to-end complete rotation.
It has been found in practice, particularly when wrapping mis-shapen and/or loosely packed bales that difficulties arise in maintaining the bale in the optimum position during the wrapping operation.
It is an object of the invention to provide improved apparatus for wrapping such baled material.